Backdoor.Zix

Symantec Security Response - Backdoor.Zix

Backdoor.Zix is a backdoor Trojan that allows a hacker to run arbitrary commands on the infected computer. The Trojan sends information an email message from the infected computer to a specific email address. It also downloads files from an email account and then executes them on the computer.

Infection Length: 90,112

technical details

When executed, the Trojan does the following:

• 
  1. It copies itself to
  
  %System%\zy6server.exe
  
  2. It adds the value
  
  iez
  
  to the registry key
  
  HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
  
  3. It attempts to register itself as a service.
  
  4. It sends system information to an email address at 163.com through the mail server smtp.163.com.
  
  5. It downloads email messages with encoded information from the POP server at pop.163.com, which instructs the computer to perform arbitrary commands.

removal instructions

These instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.

• 
  1. Update the virus definitions.
  2. Run a full system scan, and delete all the files that are detected as Backdoor.Zix.
  3. Delete the value
  
  iez
  
  from the registry key
  
  HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

Deleting the value from the registry

CAUTION: Symantec strongly recommends that you back up the registry before you make any changes to it. Incorrect changes to the registry can result in permanent data loss or corrupted files. Modify the specified keys only. Read the document How to make a backup of the Windows registry for instructions.

• 
  1. Click Start, then click Run. (The Run dialog box appears.)
  2. Type regedit, then click OK. (The Registry Editor opens.)
  3. Navigate to the key:
  
  HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
  
  4. In the right pane, delete the value
  
  iez
  
  5. Exit the Registry Editor.